While painting these flowers (a detail of a bigger painting) with cadmium yellow pale over the still wet dark green in the background I was thinking that only cadmiums can keep the full brightness over the green because of their natural opacity. Alternative pigments are more transparent and weaker, so they would let the blacks and greens come through and deaden the colour (moreover they are not as durable as cadmiums). In order to keep the brightness of the yellow colour using cadmium substitutes I should either paint the flowers in white over the green first, and wait for it to dry before painting with yellow, or draw exactly where each flower should go on the canvas before painting around with the greens, but this process would make me lose completely the freshness of the improvisation! I should say that I am in favour of finding an alternative to all poisonous pigments. However, are there valid alternatives? Not at the moment, this is why it is daunting the possibility of a ban of the cadmium pigments in Europe, leaving us artists without a comparable choice, at least until some researchers will find better quality substitutes (will it be possible?) Read more on cadmiums compared with the best available substitutes here: http://www.jacksonsart.com/blog/2014/06/13/cadmium-crisis-update/